Multi point projection welding method and loading-welding system for car-body assembly using the same

ABSTRACT

A component loading-welding system for welding a component panel to a vehicle body panel includes a rotation portion body having first and second opposing sides. The first opposing side is coupled to a robot arm. A picking device is installed in the rotation portion body and is configured to hold and release the component panel. A vehicle body pressurizing tip is installed in the rotation portion body. A pressurizing portion body is rotatably installed at the second opposing side of the rotation portion body. A pin clamp is installed in the pressurizing portion body and is configured to clamp the component panel. A component pressurizing tip is installed in the pressurizing portion body and is configured to apply pressure to the component panel. A multi point projection welding method is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is the Divisional Application of U.S. patentapplication Ser. No. 14/829,571 filed on Aug. 18, 2015, which claims thebenefit of priority to Korean Patent Application No. 10-2014-0185837filed on Dec. 22, 2014 in the Korean Intellectual Property Office, thedisclosures of which are incorporated herein in their entirety byreference.

TECHNICAL FIELD

The present disclosure relates to an apparatus for loading and welding avehicle body component, and more particularly, to a loading-weldingsystem for a car body assembly so as to perform loading and weldingcomponents of a vehicle body in one apparatus using a multi pointprojection welding method.

BACKGROUND

Most processes of loading and bonding (welding) a component panel on avehicle body panel on an automobile production line are automated.

Typically, such automation equipment includes an alignment jig foraligning a home position of a component prior to supply of a component,a gripper for gripping the aligned component, an installation homepositioning jig for aligning and pressurizing the component gripped bythe gripper at a home position of a vehicle body, and a weldingapparatus for performing spot welding in order to fix a component to anattachment position of the vehicle body, which are separatelypositioned. That is, typically, in order to install a component on thevehicle body, separate multi-step apparatuses are installed and managedfor continuous processes on a production line.

However, this typical production line structure is completed bycombining components on a sub line and is basically used in a method ofassembling complete units in a main buck. However, in this method, afloor, a side, and a roof are coupled in complete units to a vehiclebody, and thus it is necessary to weld closed sections. In addition, inthis method, components are positioned based on a pre-set assembly jig,and thus it is necessary to prepare a pre-set assembly jig for everycomponent and to change a type and position of a jig according to avehicle type. That is, it is cumbersome to prepare and re-arrange newequipment according to change in a type of vehicle to be produced. Inaddition, in spot welding, when one corresponding point of two panels ispressurized, a vehicle body is frequently distorted. In particular, thistypical equipment uses a plurality of clamping jigs, concentrationwelding is hindered.

SUMMARY

The present disclosure has been made to solve the above-mentionedproblems occurring in the prior art while advantages achieved by theprior art are maintained intact.

Certain embodiments of the present inventive concept provide atechnology for a new manufacturing process of a vehicle body, in whichcomplete units are sequentially stacked using a method different from atypical assembly method for assembling complete units in a main buck bypicking up, aligning, and gripping components of the vehicle body,loading and pressurizing the component on a position of the vehiclebody, and systemizing welding equipments as one apparatus.

Certain embodiments of the present inventive concept provide oneapparatus obtained by systemizing a picking apparatus, an aligningapparatus, a gripping apparatus, a pressurizing apparatus, a positionchecking apparatus, and a projection melting point apparatus.

According to an exemplary embodiment of the present inventive concept, amulti point projection welding method includes loading a component panelhaving one or more protrusions formed thereon onto a vehicle body panelsuch that at least one of the protrusions of the component panelcontacts the vehicle body panel. The method further includes applyingpressure to the vehicle body panel using a vehicle body pressurizing tipand applying pressure to the component panel using a componentpressurizing tip while the component panel and the vehicle body panelcontact each other, and supplying current to the vehicle bodypressurizing tip and the component pressurizing tip such that theprotrusion of the component panel contacts the vehicle body panel whilethe vehicle body pressurizing tip and the component pressurizing tipapply pressure to the vehicle body panel and the component panel,respectively.

According to another exemplary embodiment of the present inventiveconcept, a multi point projection welding method includes loading acomponent panel having one or more protrusions formed thereon onto avehicle body panel such that at least one of the protrusions of thecomponent panel contacts the vehicle body panel. The method may alsoinclude applying pressure to one side of the component panel using avehicle body pressurizing tip and applying pressure to the other side ofthe component panel using a component pressurizing tip while thecomponent panel and the vehicle body panel contact each other, andsupplying current to the vehicle body pressurizing tip and the componentpressurizing tip such that the protrusion of the component panelcontacts the vehicle body panel while the vehicle body pressurizing tipand the component pressurizing tip apply pressure to the componentpanel.

In certain embodiments, at least one of the protrusions may have aheight of 0.1 mm or more.

In certain embodiments, the current may have a magnitude of 3 to 35 kAand weld time may be 0.01 seconds to 2 seconds.

According to another exemplary embodiment of the present inventiveconcept, a component loading-welding system for welding a componentpanel to a vehicle body panel includes a rotation portion body havingfirst and second opposing sides, the first opposing side being coupledto a robot arm. A picking device is installed in the rotation portionbody and configured to hold and release the component panel. A vehiclebody pressurizing tip is installed in the rotation portion body, and apressurizing portion body is rotatably installed at the second opposingside of the rotation portion body, A pin clamp is installed in thepressurizing portion body and is configured to clamp the componentpanel. A component pressurizing tip is installed in the pressurizingportion body and configured to apply pressure to the component panel.

In certain embodiments, the picking device may be an electromagnet or avacuum suction device.

In certain embodiments, the vehicle body pressurizing tip may configuredto move forward and backward in a rotational axis direction of therotation portion body so as to apply pressure to or release pressurefrom a vehicle body by a vehicle body pressurizing moving portion.

In certain embodiments, the vehicle body pressurizing tip may be movedin a radial direction of a rotational axis of the rotation portion bodyby a radius moving portion so as to be close to or away from therotational axis of the rotation portion body.

In certain embodiments, a current generating apparatus may be installedin the rotation portion body. A conductive ring may be installed in thepressurizing portion body, exposed to the rotation portion body, andelectrically connected to the component pressurizing tip.

In certain embodiments, the vehicle body pressurizing tip may beelectrically connected to the conductive ring, and the currentgenerating apparatus may be selectively electrically connected to theconductive ring by an indirect current carrying portion.

In certain embodiments, the indirect current carrying portion may bemoved toward and away from the conductive ring by an indirect currentmoving portion so as to contact the conductive ring or separate from theconductive ring.

In certain embodiments, the pin clamp may include two pins.

In certain embodiments, a pressurizing plate with a shape correspondingto the component panel and configured to apply pressure to the componentpanel may be detachably installed in the pressurizing portion body.

In certain embodiments, the pressurizing plate may be detachablyinstalled in a pressurizing plate coupling portion of the pressurizingportion body, and the pressurizing plate coupling portion may beconnected to the pressurizing portion body using a welding forceabsorbing portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinventive concept will be more apparent from the following detaileddescription taken in conjunction with the accompanying drawings:

FIG. 1 is a schematic diagram illustrating a projection key weldingmethod;

FIG. 2 is an image showing a shape of a sectional view of a protrusionat which projection key welding is performed;

FIG. 3 is a diagram illustrating projection key welding according to anembodiment of the present inventive concept;

FIG. 4 is a diagram illustrating projection key welding according toanother embodiment of the present inventive concept;

FIG. 5 is a diagram illustrating a state in which a component panel isloaded in a component loading-welding system according to an embodimentof the present inventive concept;

FIG. 6 is a diagram illustrating a state in which a component panel ispressurized onto a vehicle body panel and projection key welding isperformed in the component loading-welding system of FIG. 5;

FIG. 7 is a perspective view illustrating a state in which a componentpanel is clamped to a component loading-welding system according to anembodiment of the present inventive concept;

FIG. 8 is a perspective view of a state in which a component panel isnot clamped to a component loading-welding system, which is viewed at adifferent angle, according to an embodiment of the present inventiveconcept;

FIG. 9 is a perspective view illustrating a state in which a rotationportion is rotated at a different angle in the component loading-weldingsystem of FIG. 8; and

FIG. 10 is a perspective view illustrating a state in which a radiusmoving portion, a vehicle pressurizing moving portion, and a componentpressurizing moving portion are moved at a rotation portion position ofFIG. 9 such that a vehicle body pressurizing tip and a componentpressurizing tip are pressurized onto a vehicle body (not shown) and acomponent (not shown) at a pressurizing position of projection keywelding.

DETAILED DESCRIPTION

Exemplary embodiments will now be described more fully with reference tothe accompanying drawings.

FIG. 1 is a schematic diagram illustrating a projection key weldingmethod. FIG. 2 is an image showing a shape of a sectional view of aprotrusion at which projection key welding is performed. FIG. 3 is adiagram illustrating projection key welding according to an embodimentof the present inventive concept. FIG. 4 is a diagram illustratingprojection key welding according to another embodiment of the presentinventive concept.

First, a multi point projection welding method according to anembodiment of the present inventive concept will now be described.

The present disclosure proposes a multi point projection welding methoddifferent from typical spot welding. As shown in FIGS. 1 and 4, in themulti point projection welding method, while a component panel P withone or more protrusions P3 formed thereon is pressurized onto a vehiclebody panel B such that a protrusion P3 of the component panel P contactsthe vehicle body panel B, a vehicle body pressurizing tip 35 ispressurized onto the vehicle body panel B and a component pressurizingtip 65 is pressurized onto the component panel P, and while the vehiclebody pressurizing tip 35 and the component pressurizing tip 65 arepressurized onto the vehicle body panel B and the component panel P,respectively, current is supplied to the vehicle body pressurizing tip35 and the component pressurizing tip 65 such that the protrusion P3 ofthe component panel P is welded to the vehicle body panel B.

As shown in FIG. 1, according to this process, the protrusion P3 and aportion of the vehicle body panel B, which contacts the protrusion P3,may be melted and welded onto each other by allowing current for weldingto flow between the component pressurizing tip 65 and the vehicle bodypressurizing tip 35 so as to be concentrated on the protrusion P3 of thecomponent panel P.

The projection welding is mainly featured in that a position of apressurizing tip at which current flows and a welding position arechanged. This means that a plurality of protrusions may besimultaneously welded by appropriately adjusting weld time and currentmagnitude according to the shape and number of protrusion.

That is, during projection welding, while the component panel ispressurized onto the vehicle body panel (in this state, the protrusionof the component panel strongly contacts the vehicle body panel), whenpressurizing tips contact a vehicle body and a component at differentpositions from the position of the protrusion and current flows, weldingis performed at a plurality of positions, and thus the number ofprocesses for welding may be reduced and also problems do not occur interms of distortion or tilt of components due to the pressurizing tipsbecause the pressurizing tip has only to contact the vehicle body andthe component as long as current flows.

Since the pressurizing tips have only to approach different positionsother when a welding point, it is very advantageous in that problems interms of interference between the pressurizing tips and a panel or otherproduction equipment may also be prevented for welding panels with acomplex shape. In particular, according to typical spot welding, weldingpoints of two panels that contact each other are pressurized onto eachother in opposite directions so as to weld the weld points, and thus itis difficult to apply the typical spot welding to a panel such as aclosed section and so on. However, according to the a multi pointprojection welding method, both pressurizing tips may approach the panelin one direction of the panel, and thus there is no limit in applyingthe multi point projection welding method to a vehicle body structurethat is difficult to approach, such as a closed section and so on.

In particular, the problem in terms of strength of welding that proceedsin one direction may be overcome by forming a protrusion on a panel andlocally concentrating current.

As shown in FIG. 2, the height H of the protrusion of the panel may beappropriately adjusted according to a welding condition. In certainembodiments, the height H may be at least a minimum of 0.1 mm. Incertain embodiments, current may have a magnitude of about 3 to 35 kAaccording to a type of a used welder. That is, the current magnitude maybe changed according to a material and a thickness thereof, and in thecase of a MF DC welder, the current magnitude may be adjusted to 20 kAfrom 3 kA, and in the case of a capacitor welder, the current magnitudemay be adjusted up to 35 kA.

In certain embodiments, with regard to weld time, current may flow for0.01 second to 1 second, and in the case of multi-step welding, currentmay flow for maximum of 2 seconds and target points may be welded.

According to the present disclosure, two welding portions of multi pointprojection welding do not have to pressurize the vehicle body panel andthe component panel. For example, as shown in FIG. 3, the vehicle bodypressurizing tip 35 may be pressurized onto one side of the componentpanel, and the component pressurizing tip 65 may be pressurized onto theother side of the component panel.

According to this welding method, a plurality of clamps that are used tofix a component to a typical jig may be omitted, and a trajectory alongwhich a robot performs many operations may be simplified in order toprevent interference of jig, which is advantageous for ensuring cycletime.

FIG. 5 is a diagram illustrating a state in which a component panel isloaded in a component loading-welding system according to an embodimentof the present inventive concept. FIG. 6 is a diagram illustrating astate in which a component panel is pressurized onto a vehicle bodypanel and projection key welding is performed in the componentloading-welding system of FIG. 5. FIG. 7 is a perspective viewillustrating a state in which a component panel is clamped to acomponent loading-welding system according to an embodiment of thepresent inventive concept. FIG. 8 is a perspective view of a state inwhich a component panel is not clamped to a component loading-weldingsystem, which is viewed at a different angle, according to an embodimentof the present inventive concept. FIG. 9 is a perspective viewillustrating a state in which a rotation portion is rotated at adifferent angle in the component loading-welding system of FIG. 8. FIG.10 is a perspective view illustrating a state in which a radius movingportion, a vehicle body pressurizing moving portion, and a componentpressurizing moving portion are moved at a rotation portion position ofFIG. 9 such that a vehicle body pressurizing tip and a componentpressurizing tip are pressurized onto a vehicle body (not shown) and acomponent (not shown) at a pressurizing position of projection keywelding.

Hereinafter, a component loading-welding system 1 using theaforementioned multi point projection welding method will be described.According to an embodiment of the multi point projection welding method,even if both two pressurizing tips approach one side of a panel, noproblem arises, and thus the pressurizing tips 35 and 65 for welding maybe integrated with a component panel pressurizing apparatus and oneapparatus.

First, the component loading-welding system 1 according to an embodimentof the present inventive concept may be fixed to an end of a robot armR, a position of the component loading-welding system 1 may be adjustedby the robot arm R, and a rotation portion 11 and a pressurizing portion13 may be relatively rotated. This is an integration system, and thus asshown in FIG. 5, the component panel P may be clamped by the system 1from a component supplying box S, and as shown in FIG. 6, the robot armR and the system 1 align and apply pressure to the component panel P ata home position of the vehicle body panel B and simultaneously thevehicle body pressurizing tip 35 and the component pressurizing tip 65are pressurized to the vehicle body panel and the component panel andcurrent flows so as to weld the vehicle body panel and the componentpanel via welding in the system 1. That is, it is possible to clamp acomponent panel by one system 1 and to weld the component panel to thevehicle body panel.

A structure of the system 1 will be described in detail. As shown inFIG. 7, the system 1 includes the rotation portion 11 with one endcoupled to the robot arm R and the pressurizing portion 13 coupled tothe other end of the rotation portion 11.

The robot arm R may be coupled to the rotation portion 11 and mayrelatively rotate the rotation portion 11 and the pressurizing portion13. The rotation portion 11 includes a rotation portion body 110 thatconstitutes a frame thereof and the pressurizing portion 13 may alsoinclude a pressurizing portion body 130 that constitutes a framethereof. The robot arm R is coupled to the rotation portion body 110.The rotation portion body 110 and the pressurizing portion body 130 arerotatably coupled around a rotational axis.

The pressurizing portion body 130 is disposed at an opposite position tothe robot arm R based on the rotation portion body 110, and thus thepressurizing portion 13 may load the component panel P onto the vehiclebody panel B toward an axial direction of a rotation axis of relationrotation of the rotation portion 11 and the pressurizing portion 13.

The rotation portion body 110 includes a picking device 20 for holdingand releasing of the component panel P. The picking device 20 isinstalled on and is integrally operated with the rotation portion body110. In certain embodiments, the picking device 20 may be anelectromagnet or a vacuum suction device. In certain embodiments, thepicking device 20 may be used to pick up one component from componentsthat are stacked on each other, and may temporarily pick up thecomponent panel from a component stack and re-put it on a temporarystorage place of the component. That is, in certain embodiments, when arobot arm is moved to reach an upper portion of stacked components whilea vacuum is formed in a vacuum suction device, for example, a vacuum cupof an end of the picking device 20, the component panel is held by thepicking device 20 due to vacuum. In this embodiment, while the robot armis moved and the component panel is held by the picking device 20, whenthe component panel is put on the temporary storage place and vacuumsuction of the picking device 20 is released, one component panel may beput on the temporary storage place. As such, the component panel movedto the temporary storage place is fixed to the pressurizing portion 13by a pin clamp 70.

The component panel P is moved to a home position of the vehicle bodypanel and is pressurized by a pressurizing plate 50 of the pressurizingportion 13, and the picking device is a device that is temporarily usedto pick up one component panel from a plurality of component panels.

In certain embodiments, the pin clamp 70 includes at least two pins.Thus, the robot arm may be moved to allow the pin clamp 70 to approach acomponent panel put on a temporary storage place so as to accuratelyalign and clamp the component panel by the pin clamp 70.

As illustrated in FIG. 7, the pressurizing plate 50 is fixed to an innerportion (an upper portion in FIG. 7) of the clamped component panel P.The pressurizing plate 50 has a shape corresponding to the componentpanel P so as to stably load the component panel to a vehicle bodyduring pressurization of the component panel to the vehicle body. Thepressurizing plate 50 may be changed according to a vehicle type or atype of the component panel P. In certain embodiments, the pressurizingplate 50 is detachably installed in a pressurizing plate couplingportion 53 installed in the pressurizing portion body 130 using awelding force absorbing portion 55, which in certain embodiments is aspring, as a medium. Accordingly, in certain embodiments, when the robotarm is pressured toward the vehicle body in a rotation axis of thesystem, the pressurizing plate 50 installed in the pressurizing platecoupling portion 53 stably pressurizes the component panel to a homeposition, and thus a pressurizing force is absorbed into the weldingforce absorbing portion 55 as a spring, thereby preventing the componentpanel or the vehicle body panel from being changed due to force of therobot arm.

While the pressurizing plate 50 pressurizes the component panel P ontothe vehicle body panel B, embodiments of the aforementioned multi pointprojection welding method may be used. To this end, the system accordingto embodiments of the present inventive concept is configured in such away that the vehicle body pressurizing tip 35 is installed in therotation portion body 110 and the component pressurizing tip 65 forpressurizing the component panel P is installed in the pressurizingportion body 130.

Since the component pressurizing tip 65 is installed in the pressurizingportion 13, the component pressurizing tip 65 installed in thepressurizing portion 13 is also fixed to the pin clamp 70, and pressureto the component panel P pressurized by the pressurizing plate 50 may beeasily applied or released. In certain embodiments, the componentpressurizing tip 65 is also moved forward and backward by a componentpressurizing moving portion 63 installed in the pressurizing portion 13.

The vehicle body pressurizing tip 35 is moved to a portion of a vehiclebody, to be pressurized, and then is pressurized. To this end, incertain embodiments, a position of the vehicle body pressurizing tip 35is adjusted by relatively rotating the rotation portion body 110 withrespect to the pressurizing portion body 130 to adjust a directionalangle and then moving the rotation portion body 110 in a radialdirection of a rotational axis of a rotation portion by a radius movingportion 31 so as to be close to or away from the rotational axis of therotation portion. As such, in certain embodiments, according to rotationof the rotation portion and an operation of the radius moving portion,the vehicle body pressurizing tip that is accurately aligned is movedforward and backward in the same direction as a rotational axisdirection of the rotation portion by a vehicle body pressurizing movingportion 33 so as to apply pressure to or release pressure from thevehicle body. A position of the vehicle body to be pressurized by thevehicle body pressurizing tip may be changed according to a vehicletype, and a type and position of a component panel to which the vehiclebody panel is welded. As such, the vehicle body pressurizing tip may bealigned and an operation is performed according to rotation of therotation portion and radius-adjustment of the radius moving portion 31,and thus a typical technology of newly aligning jigs for every componentand every vehicle type may be flexibly and widely used withoutcumbersome.

The system 1 according to embodiments of the present inventive conceptis configured to achieve the following weld structure of the vehiclebody pressurizing tip 35 and the component pressurizing tip 65 so as tofreely rotate the rotation portion and the pressurizing portion.

In certain embodiments, a current generating apparatus 40 is installedin the rotation portion body 110, a conductive ring 43 exposed to arotation portion body is installed in the pressurizing portion body 130,and the conductive ring 43 is electrically connected to the componentpressurizing tip 65. Both the conductive ring 43 and the componentpressurizing tip are included in the pressurizing portion body 130, andthus the conductive ring 43 and the component pressurizing tip may beelectrically connected irrespective of rotation of the rotation portion11.

In certain embodiments, the vehicle body pressurizing tip 35 may also beelectrically connected to the conductive ring 43. In certainembodiments, the vehicle body pressurizing tip 35 may be relativelyrotated with respect to the conductive ring 43, and thus vehicle bodypressurizing tip 35 and the conductive ring 43 may be connected using anelastic terminal and so on so as to be electrically connected to eachother while being relatively moved with respect to each other. On theother hand, in certain embodiments, since the vehicle body pressurizingtip 35 is integrally rotated with the current generating apparatus 40,the vehicle body pressurizing tip 35 may be electrically connecteddirectly to the current generating apparatus 40.

In certain embodiments, the current generating apparatus 40 may beselectively and electrically connected to the conductive ring 43 by anindirect current carrying portion 41. The indirect current carryingportion 41 may be moved forward and backward the conductive ring 43 byan indirect current moving portion 45 so as to contact the conductivering 43 or contact-release from the conductive ring 43, and thus theindirect current carrying portion 41 may be electrically connected to ordisconnected from the conductive ring 43.

Accordingly, in certain embodiments, when the vehicle body pressurizingtip 35 is positioned at a home position according to rotation of therotation portion and movement of a position of the radius movingportion, all of the indirect current moving portion 45, the vehicle bodypressurizing moving portion 33, and the component pressurizing movingportion 63 may advance the indirect current carrying portion 41, thevehicle body pressurizing tip 35, and the component pressurizing tip 65so as to contact the conductive ring 43, the vehicle body panel, and thecomponent panel, respectively and to allow current to flow, and thuswelding may be performed.

After welding, while the indirect current carrying portion, the vehiclebody pressurizing tip, and the component pressurizing tip may be movedbackward and clamping of a pin clamp is released, the robot arm movesthe system 1 away from the vehicle body, thereby completing anoperation.

The system according to the embodiments of the present inventive conceptmay simultaneously perform clamping, alignment, and welding of componentusing only one system.

In addition, in certain embodiments, a production process may be moreefficiently performed by further adding a vision apparatus, a homeposition ensuring apparatus, and a welding apparatus to a productionline.

According to embodiments of the present inventive concept, the number ofequipments and processes may be minimized and a new type of assemblytechnology of a vehicle body may be ensured. That is, all sub lines forcompletion may be integrated into a main line, thereby simplifying anentire process.

In addition, in certain embodiments, a plurality of points (dimpleforming portions) positioned at a different position from a pressurizingportion may be simultaneously welded via one welding operation.

When a component is supplied to a box, component movement and projectionkey welding may be performed by one system, thereby simplifying aproduction line and ensuring a space.

In certain embodiments, unit components may be sequentially stacked andwelded to form an entire structure.

Unit components may be sequentially welded, thereby minimizing a weldingportion for a closed section.

In certain embodiments, a current position of a component to be attachedmay be recognized and corrected and moved to a home position, and thuserrors may be continuously corrected even if the same operation isrepeated several hundred times.

In certain embodiments, a vehicle body may be prevented from beingdistorted during spot welding through projection key welding.

In addition, use of clamp may be minimized during projection keywelding, and thus concentration welding is possible.

While embodiments of the present inventive concept has been particularlyshown and described with reference to exemplary drawings thereof, itwill be understood by those of ordinary skill in the art that variouschanges in form and details may be made therein without departing fromthe spirit of the present inventive concept as defined by the followingclaims.

What is claimed is:
 1. A multi point projection welding methodcomprising: loading a component panel having one or more protrusionsformed thereon onto a vehicle body panel, such that the one or moreprotrusions of the component panel contacts the vehicle body panel atone or more welding positions; applying pressure to a first side of thecomponent panel at a first contact position using a vehicle bodypressurizing tip, and applying pressure to a second side of thecomponent panel at a second contact position using a componentpressurizing tip while the component panel and the vehicle body panelcontact each other; and supplying current to the vehicle bodypressurizing tip and the component pressurizing tip, such that the oneor more protrusions of the component panel and a portion of the vehiclebody panel that contacting the one or more protrusions are welded ontoeach other while the vehicle body pressurizing tip and the componentpressurizing tip apply pressure to the component panel, wherein thefirst contact position between the first side of the component panel andthe vehicle body pressurizing tip is different from each contactposition of the one or more protrusions contacting the vehicle bodypanel, the vehicle body pressurizing tip is not aligned with any of theone or more protrusions; wherein the second contact position between thesecond side of the component panel and the component pressurizing tip isdifferent from each contact position of the one or more protrusionscontacting the vehicle body panel, the component pressurizing tip is notaligned with any of the one or more protrusions; and wherein the one ormore welding positions are located between the first contact positionand the second contact position.
 2. The multi point projection weldingmethod according to claim 1, wherein at least one of the protrusions hasa height of 0.1 mm or more.
 3. The multi point projection welding methodaccording to claim 1, wherein the current has a magnitude of 3 to 35 kAand weld time is 0.01 seconds to 2 seconds.